databases/redis{6,62}: Fix problem that pkg-message is misleading

When installing package of databases/redis62, following pkg-message is
displayed.

To setup "redis62" you need to edit the configuration file:
/usr/local/etc/redis62.conf

To run redis from startup, add redis62_enable="YES"
in your /etc/rc.conf.

But path of configuration file is /usr/local/etc/redis.conf and what
should really be added to /etc/rc.conf is redis_enable="YES". Same
problem also happens when installing databases/redis6

The source of the problem is that the value of ${PORTNAME} is used to
create pkg-message from file/pkg-message.in. So fix it by changing the
value of ${PORTNAME} to "redis" and set PKGNAMESUFFIX in Makefile of
each port.

While I'm here,

• Pet portlint and portclippy
• Tidy up Makefile with portfmt.

PR: 265623
Reported by: FiLiS
MFH: 2022Q3